Radiation detector module

ABSTRACT

A radiation detector module  10 A includes a scintillator for converting radiation made incident from a predetermined direction to light, a two-dimensional PD array  12  for receiving light from the scintillator, a connection substrate  13  formed by stacking dielectric layers  130   a  to  130   f , and mounted with the two-dimensional PD array  12  on one substrate surface thereof, and an integrated circuit device  14  mounted on the other substrate surface of the connection substrate  13 , and for reading out electrical signals output from the two-dimensional PD array  12 . The integrated circuit device  14  has a plurality of unit circuit regions  14   b  separated from each other. The connection substrate  13  has a plurality of through conductors  20  and a plurality of radiation shielding films  21   a  to  23   a  formed integrally with each of the plurality of through conductors  20  and separated from each other. Accordingly, the readout circuits of the integrated circuit device can be protected from radiation with a simple configuration.

TECHNICAL FIELD

The present invention relates to a radiation detector module.

BACKGROUND ART

Patent Document 1 describes an X-ray CT device having a configurationfor protecting a signal processing circuit provided in an X-ray detectorfrom exposure to X-rays. In this X-ray CT device, on a back surface sideof a wiring board with a detection element mounted at its front surface,a circuit board mounted with a signal processing circuit is disposed. Inthe wiring board, an X-ray shielding portion is placed so as to coverthe signal processing circuit from above. The wiring board and circuitboard are electrically connected to each other by a connecting memberprovided around the X-ray shielding portion.

Patent Document 2 describes a medical diagnostic imaging device usingX-rays and an X-ray radiation detector. This X-ray radiation detectorincludes a supporting substrate. The supporting substrate supports aphotosensitive element on its front surface side, and provides anelectrical path to its rear surface side. Between the supportingsubstrate and a signal processing circuit, an X-ray radiation shieldingportion is disposed. The area of the X-ray radiation shielding portionviewed from an X-ray incident direction is larger than that of thesignal processing circuit included in an ASIC readout chip.

CITATION LIST Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2009-189384

-   Patent Document 2: Japanese Translation of International Application    No. 2004-536313

SUMMARY OF INVENTION Technical Problem

In recent years, as radiation detectors for X-ray inspection apparatusesand the like, devices including photoelectric conversion devices such asphotodiode arrays having pluralities of two-dimensionally arrayedphotoelectric conversion regions and scintillators disposed on thephotoelectric conversion devices have been put into practical use. Ascompared with conventional detectors using X-ray sensitive films, suchradiation detectors offer a high level of convenience such as notrequiring development and being able to confirm images in real time, andare also excellent in data storage and ease in handling.

In such radiation detectors, the photoelectric conversion device ismounted on a substrate in most cases. Moreover, because it is necessaryto amplify minute signals output from the photoelectric conversiondevice, an integrated circuit device having a plurality of built-inreadout circuits such as a plurality of integrator circuitscorresponding to the plurality of photoelectric conversion regions isused. The plurality of readout circuits consist of, for example,integrator circuits. It is preferable that the integrated circuit deviceis mounted on the backside of the substrate for downsizing of thedevice.

However, when the photoelectric conversion device is mounted on one ofthe substrate surfaces of the substrate, and the integrated circuitdevice is mounted on the other substrate surface, the following problemoccurs. That is, when radiation made incident into the scintillator istransmitted in part without being absorbed in the scintillator, theradiation may be transmitted through the substrate to reach theintegrated circuit device. In the readout circuits of the integratedcircuit device, circuit elements that are easily affected by radiationsuch as, for example, operational amplifiers, capacitors, or switchingMOS transistors are included. Hence, radiation having reached theintegrated circuit device may cause an abnormality in the circuitelements. Therefore, it is demanded to protect the readout circuits fromradiation by some measure.

Also, in the devices described in Patent Documents 1 and 2, a radiationshield having a size such as to cover the whole integrated circuitdevice is provided in the substrate. However, in such a configuration,wiring for connection between the photoelectric conversion device andthe integrated circuit device must be disposed so as to bypass theradiation shield. Therefore, in the case such as, for example, flip-chipbonding the photoelectric conversion device and the integrated circuitdevice onto the substrate, substrate wiring is complicated.

It is an object of the present invention to provide a radiation detectormodule capable of protecting readout circuits of an integrated circuitdevice from radiation with a simple configuration.

Solution to Problem

A radiation detector module according to an embodiment of the presentinvention includes (a1) a scintillator for converting radiation madeincident from a predetermined direction to light, (b) a photoelectricconversion device having a plurality of photoelectric conversion regionsarrayed two-dimensionally, and for receiving light from the scintillatorat the photoelectric conversion regions, (c) a connection substrateformed by stacking a plurality of dielectric layers, and mounted withthe photoelectric conversion device on one substrate surface thereof,and (d) an integrated circuit device mounted on the other substratesurface of the connection substrate, and for individually reading outelectrical signals output from each of the plurality of photoelectricconversion regions of the photoelectric conversion device. Theintegrated circuit device has a plurality of unit circuit regions. Theplurality of unit circuit regions are arrayed two-dimensionally andseparated from each other. The plurality of unit circuit regions includea plurality of readout circuits corresponding to the plurality ofphotoelectric conversion regions, respectively. The connection substratehas a plurality of metallic through conductors. The plurality of throughconductors are provided penetrating through at least three dielectriclayers adjacent to each other out of the plurality of dielectric layers.The plurality of through conductors serve as a part of paths for theelectric signals. In this radiation detector module, a plurality ofmetallic radiation shielding films are provided at two or moreinterlayer parts in the at least three dielectric layers. The pluralityof radiation shielding films are formed integrally with each of theplurality of through conductors, and separated from each other. Each ofa plurality of first regions of projection of the plurality of radiationshielding films onto a virtual plane normal to the predetermineddirection includes each of a plurality of second regions of projectionof the plurality of unit circuit regions onto the virtual plane.

Moreover, a radiation detector module according to another embodiment ofthe present invention includes (a2) a scintillator for convertingradiation to light, (b) a photoelectric conversion device having aplurality of photoelectric conversion regions arrayed two-dimensionally,and for receiving light from the scintillator at the photoelectricconversion regions, (c) a connection substrate formed by stacking aplurality of dielectric layers, and mounted with the photoelectricconversion device on one substrate surface thereof, and (d) anintegrated circuit device mounted on the other substrate surface of theconnection substrate, and for individually reading out electricalsignals output from each of the plurality of photoelectric conversionregions of the photoelectric conversion device. The integrated circuitdevice has a plurality of unit circuit regions. The plurality of unitcircuit regions are arrayed two-dimensionally and separated from eachother. The plurality of unit circuit regions include a plurality ofreadout circuits corresponding to the plurality of photoelectricconversion regions, respectively. The connection substrate has aplurality of metallic through conductors. The plurality of throughconductors are provided penetrating through at least three dielectriclayers adjacent to each other out of the plurality of dielectric layers.The plurality of through conductors serve as a part of paths for theelectric signals. In this radiation detector module, a plurality ofmetallic radiation shielding films are provided at two or moreinterlayer parts in the at least three dielectric layers. The pluralityof radiation shielding films are formed integrally with each of theplurality of through conductors, and separated from each other. Each ofa plurality of first regions of projection of the plurality of radiationshielding films onto a virtual plane parallel to the one substratesurface includes each of a plurality of second regions of projection ofthe plurality of unit circuit regions onto the virtual plane.

In these radiation detector modules, the integrated circuit devicemounted on the other substrate surface of the connection substrate has aplurality of unit circuit regions including a plurality of readoutcircuits respectively. In addition, these plurality of unit circuitregions are arrayed two-dimensionally and separated from each other.Therefore, regarding gaps between these unit circuit regions, there islittle influence from radiation because no readout circuits exist.

On the other hand, in the connection substrate, a plurality of throughconductors that penetrate through at least three dielectric layers and aplurality of metallic radiation shielding films formed integrally witheach of the plurality of through conductors are provided. Thus, theradiation shielding films formed integrally with the through conductorsdo not obstruct arrangement of the through conductors, so that it is notnecessary to form a complicated wiring such as to bypass a radiationshield as in, for example, the device described in Patent Document 1.Therefore, the current path, that is, the wiring length between thephotoelectric conversion device and the integrated circuit device can bereduced, and noise to be superimposed on a photoelectric current can befurther reduced.

In addition, these plurality of metallic radiation shielding films areseparated from each other and provided at two or more interlayer partsin the at least three dielectric layers. Further, each of the pluralityof first regions of projection of the plurality of radiation shieldingfilms onto a virtual plane includes each of the plurality of secondregions of projection of the plurality of unit circuit regions onto thevirtual plane. Here, the virtual plane is a plane normal to thepredetermined direction, that is, the radiation incident direction.Alternatively, when the radiation incident direction is normal to thesubstrate surfaces of the connection substrate, the virtual plane is aplane parallel to one of the substrate surfaces of the connectionsubstrate. Due to such a configuration, each of the pluralities ofradiation shielding films formed inside the connection substrateprotects each corresponding unit circuit region from radiation.Moreover, radiation that has passed through the gaps between thepluralities of radiation shielding films can reach the integratedcircuit device, but there is no problem because the part of arrivalcorresponds to gaps between the plurality of unit circuit regions.

As described in the above, by the radiation detector module describedabove, the readout circuits of the integrated circuit device can beprotected from radiation with a simple configuration.

Moreover, in the radiation detector module described above, theplurality of unit circuit regions of the integrated circuit device areseparated from each other. Therefore, noise to be generated byelectrical crosstalk between the plurality of unit circuit regions canbe reduced.

Moreover, in the radiation detector module described above, the firstregion for the radiation shielding film formed integrally with onethrough conductor in one interlayer part and the first region for theradiation shielding film formed integrally with another throughconductor in another interlayer part may not overlap each other.Accordingly, the radiation shielding films formed integrally with eachof the one through conductor and the other through conductor are notopposed to each other, so that a parasitic capacitance to be generatedbetween the one through conductor and the other through conductor can bereduced. Therefore, noise to be superimposed on photoelectric currentsoutput from the plurality of photoelectric conversion regions of thephotoelectric conversion device can be reduced.

Moreover, in the radiation detector module described above, each of aplurality of third regions of projection of the plurality of throughconductors onto the virtual plane may be included in each of theplurality of second regions, and each radiation shielding film may beextended around each corresponding through conductor.

Moreover, in the radiation detector module described above, the readoutcircuit may include an operational amplifier, a capacitor, and a MOStransistor.

Advantageous Effects of Invention

By the radiation detector module according to the present invention, thereadout circuits of the integrated circuit device can be protected fromradiation with a simple configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view showing an embodiment of a radiation detectormodule.

FIG. 2 is a sectional view showing an internal configuration of aconnection substrate and integrated circuit device.

FIG. 3 shows an arrangement of structural elements of an integratedcircuit device viewed from an incident direction of radiation.

FIG. 4 is an equivalent circuit diagram showing a configuration exampleof a readout circuit.

FIG. 5 is a view showing projection of radiation shielding films andunit circuit regions onto a virtual plane.

FIG. 6 is a sectional view showing a modification of a radiationdetector module.

FIG. 7 is a view showing projection of radiation shielding films andunit circuit regions onto a virtual plane in the modification.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of a radiation detector module according to thepresent invention will be described in detail with reference to theaccompanying drawings. Also, the same elements will be denoted with thesame reference signs in the description of drawings, and overlappingdescription will be omitted.

FIG. 1 is a sectional view showing a configuration of an embodiment of aradiation detector module. The radiation detector module 10A shown inFIG. 1 includes a scintillator 11, a photodiode array 12, a connectionsubstrate 13, and an integrated circuit device 14.

The scintillator 11 is a plate-shaped member for converting radiation Rmade incident from a predetermined direction to light. The radiation Ris, for example, X-rays. The scintillator 11 is divided into a pluralityof pixels arrayed in M rows and N columns, and disposed on a lightincident surface of the two-dimensional photodiode array 12. N and M areboth integers not less than 2. The scintillator 11 producesscintillation light in response to the incident radiation R to convert aradiation image into a light image, and outputs the light image to thetwo-dimensional photodiode array 12. The scintillator 11 is made of, forexample, CsI. The scintillator 11 can be placed so as to cover thetwo-dimensional photodiode array 12, or can be provided by vapordeposition on the two-dimensional photodiode array 12.

The two-dimensional photodiode array 12 serves as a photoelectricconversion device in the present embodiment. The two-dimensionalphotodiode array 12 has a plurality of photodiodes as a plurality ofphotoelectric conversion regions arrayed two-dimensionally such as in Mrows and N columns, and receives light from the scintillator 11 at theplurality of photodiodes. The two-dimensional photodiode array 12 has aplurality of bump electrodes 12 a, which is a conductive bondingmaterial for so-called flip-chip bonding, on a back surface on theopposite side to the light incident surface, and these plurality of bumpelectrodes 12 a are arrayed two-dimensionally such as in M rows and Ncolumns on the back surface of the two-dimensional photodiode array 12.The two-dimensional photodiode array 12 has planar dimensions of, forexample, 20 mm×35 mm.

The connection substrate 13 is mounted with the two-dimensionalphotodiode array 12 on one substrate surface 13 a, and is mounted withthe integrated circuit device 14 to be described later on the othersubstrate surface 13 b. The connection substrate 13 is formed bystacking a plurality of dielectric layers, and has an internal wiringfor electrical connection between the two-dimensional photodiode array12 and the integrated circuit device 14. Moreover, on the one substratesurface 13 a of the connection substrate 13, a plurality of land-shapedwirings to mount the two-dimensional photodiode array 12 are arrayedtwo-dimensionally such as in M rows and N columns, and on the othersubstrate surface 13 b, a plurality of land-shaped wirings to mount theintegrated circuit device 14 are arrayed two-dimensionally.

The integrated circuit device 14 individually detects electrical signalssuch as a photoelectric current output from each of the plurality ofphotodiodes of the two-dimensional photodiode array 12 to thereby readout these electric signals. The integrated circuit device 14 has astructure for which a plurality of readout circuits corresponding to theplurality of photodiodes of the two-dimensional photodiode array 12 arecollectively packaged into a chip. Moreover, a plurality of bumpelectrodes 14 a as a conductive bonding material to serve as inputterminals to these plurality of readout circuits are arrayedtwo-dimensionally on a surface of the integrated circuit device 14opposed to the connection substrate 13.

Moreover, the radiation detector module 10A further includes a flexibleprinted board 15 to externally output an electrical signal output fromthe integrated circuit device 14. One end of the flexible printed board15 is electrically connected onto the other substrate surface 13 b ofthe connection substrate 13.

Moreover, the radiation detector module 10A further includes a heat sink16 to cool the integrated circuit device 14. The heat sink 16 is incontact with a surface of the integrated circuit device 14 on theopposite side to the surface opposed to the connection substrate 13, andhas a shape of a large number of fins projecting to the outside.

FIG. 2 is a sectional view showing an internal configuration of theconnection substrate 13 and the integrated circuit device 14. In thesame figure, there is illustrated a two-dimensional photodiode array 12,but illustration of a scintillator 11 and a heat sink 16 is omitted.

As shown in FIG. 2, the integrated circuit device 14 has a plurality ofunit circuit regions 14 b and a plurality of circuit regions 14 c. Inthe plurality of unit circuit regions 14 b, a plurality of front-stageamplifiers are respectively included as a plurality of readout circuits.These plurality of readout circuits respectively correspond to theplurality of photodiodes of the two-dimensional photodiode array 12, andrespectively receive electrical signals such as photoelectric currentsfrom the corresponding photodiodes. In the circuit region 14 c, arear-stage amplifier is provided as an amplifier circuit to furtheramplify a signal output from the readout circuit of the unit circuitregion 14 b.

Here, Part (a) of FIG. 3 is a view showing a configuration example ofthe integrated circuit device 14. Part (a) of FIG. 3 shows anarrangement of the structural elements of the integrated circuit device14 viewed from an incident direction of radiation R. Part (b) of FIG. 3is a view showing one of the unit circuit regions 14 b of the integratedcircuit device 14 in an enlarged manner. The integrated circuit device14 has a size of, for example, 9 mm×11 mm.

As shown in Part (a) of FIG. 3, the unit circuit regions 14 b arearrayed two-dimensionally in J rows and K columns in the interior of theintegrated circuit device 14. J and K are integers not less than 2. Ineach unit circuit region 14 b, an input pad 14 e is provided as shown inPart (b) of FIG. 3. On the input pad 14 e, the bump electrode 14 a shownin FIG. 1 is provided. Moreover, these unit circuit regions 14 b areseparated from each other, and between one unit circuit region 14 b andother unit circuit regions 14 b, a region where no circuit elements suchas transistors and capacitors exist extends in the row direction andcolumn direction. However, in this region, a metal wiring to connectcircuit elements to each other may exist. A single unit circuit region14 b has dimensions of, for example, 0.5 mm in the row direction and 0.5mm in the column direction, and the gap interval between the neighboringunit circuit regions 14 b is, for example, 0.16 mm.

K circuit regions 14 c are disposed corresponding to the columns of theunit circuit regions 14 b. These circuit regions 14 c are disposedaligned in the row direction, and their input ends are electricallyconnected with the unit circuit regions 14 b of the correspondingcolumns, respectively.

In the front-stage amplifier as a readout circuit included in the unitcircuit region 14 b and the rear-stage amplifier as an amplifier circuitincluded in the circuit region 14 c, switches are individually provided.Designation of a row to be read out can be performed by using the switchof the readout circuit of the unit circuit region 14 b, and designationof a column to be read out can be performed by using the switch of theamplifier circuit of the circuit region 14 c.

Output ends of the K circuit regions 14 c are electrically connectedwith an A/D converter 14 d. The A/D converter 14 d converts an analogsignal output from each circuit region 14 c to a digital signal. Thedigital signal output from the A/D converter 14 d is output to theoutside of the integrated circuit device 14 via one of the plurality ofinput/output pads 14 f arrayed along an edge of the integrated circuitdevice 14. Other input/output pads 14 f are used for power supplyvoltage input, input of a reference potential such as a groundpotential, clock input, and the like.

FIG. 4 is an equivalent circuit showing a configuration example of thereadout circuit included in each unit circuit region 14 b. In thisequivalent circuit, the readout circuit 140 consists of an integratorcircuit, and includes an operational amplifier 141, a capacitor 142 as afeedback capacitance, and a reset switch 143. A non-inverting inputterminal of the operational amplifier 141 is connected to a referencevoltage Vref, and an inverting input terminal of the operationalamplifier 141 is connected to an anode of one of the photodiodes 12 bincluded in the two-dimensional photodiode array 12 shown in FIG. 1. Acathode of the photodiode 12 b is connected to the reference voltageVref, and a reverse bias is applied to the photodiode 12 b.

The capacitor 142 is connected between the inverting input terminal andoutput terminal of the operational amplifier 141. In the capacitor 142,a charge due to a photoelectric current output from the photodiode 12 bis accumulated. The reset switch 143 is connected in parallel to thecapacitor 142, and resets the charge accumulated in the capacitor 142.The reset switch 143 is suitably realized by, for example, a MOStransistor.

Referring again to FIG. 2, the connection substrate 13 will be describedin detail. The connection substrate 13 of the present embodiment has abase material 130 formed by stacking a plurality of dielectric layers130 a to 130 f. In FIG. 2, six dielectric layers 130 a to 130 f areshown. The dielectric layers 130 a to 130 f of the base material 130 areformed of, for example, a ceramic substrate made mainly from a ceramicmaterial such as alumina. The thickness of each of the dielectric layers130 a to 130 f is, for example, not less than 100 μm and not more than200 μm.

Moreover, the connection substrate 13 has a plurality of throughconductors 20. The through conductor 20 is provided penetrating throughat least three dielectric layers 130 c to 130 f adjacent to each otherout of the dielectric layers 130 a to 130 f. In one example, the throughconductor 20 is provided penetrating through four dielectric layers 130c to 130 f. Each of the plurality of through conductors 20 correspondsone-to-one to each of the plurality of photodiodes of thetwo-dimensional photodiode array 12, and serves as a part of a path fora photoelectric current output from the photodiode. The throughconductor 20 is made of, for example, a metal material such as tungsten,and is formed by the metal material being implanted into a through-holeformed in the dielectric layers 130 c to 130 f In the presentembodiment, the pitch of the neighboring through conductors 20 is equalto the pitch between the unit circuit regions 14 b of the integratedcircuit device 14, so that each through conductor 20 is locatedimmediately above the corresponding unit circuit region 14 b. The pitchof the neighboring through conductors 20 is, for example, 500 μm.Moreover, the diameter of the through conductors 20 is, for example, 100μm.

Moreover, the connection substrate 13 has a plurality of radiationshielding film groups 21 to 23 provided at two or more interlayer partsin the at least three dielectric layers 130 c to 130 f. In FIG. 2, theplurality of radiation shielding film groups 21 to 23 are provided atthree interlayer parts in four dielectric layers 130 c to 130 f.Specifically, the radiation shielding film group 21 is provided at aninterlayer part between the dielectric layers 130 c and 130 d, theradiation shielding film group 22 is provided at an interlayer partbetween the dielectric layers 130 d and 130 e, and the radiationshielding film group 23 is provided at an interlayer part between thedielectric layers 130 e and 130 f.

Each of the radiation shielding film groups 21 to 23 includes aplurality of metallic radiation shielding films corresponding to thenumber of through conductors 20. That is, the radiation shielding filmgroup 21 includes the same number of radiation shielding films 21 a asthat of the through conductors 20, the radiation shielding film group 22includes the same number of radiation shielding films 22 a as that ofthe through conductors 20, and the radiation shielding film group 23includes the same number of radiation shielding films 23 a as that ofthe through conductors 20. These radiation shielding films 21 a to 23 aare formed integrally with their corresponding through conductors 20,and extended around said through conductors 20.

In the respective radiation shielding film groups 21 to 23, theradiation shielding films are separated from each other. That is, theplurality of radiation shielding films 21 a are provided at intervalsfrom each other in one interlayer part, the plurality of radiationshielding films 22 a are provided at intervals from each other inanother interlayer part, and the plurality of radiation shielding films23 a are provided at intervals from each other in still anotherinterlayer part. Thereby, the through conductors 20 are electricallyisolated.

The planar shape of the radiation shielding films 21 a is, for example,a regular square of 400 μm square. Moreover, the interval of theneighboring radiation shielding films 21 a is, for example, 100 μm, andthe thickness of the radiation shielding films 21 a is, for example, 10μm. The shape and dimensions are the same as for the radiation shieldingfilms 22 a, 23 a. As the constituent material of the radiation shieldingfilms 21 a to 23 a, for example, tungsten is suitable. The radiationshielding films 21 a to 23 a can be easily formed by the same method asthe method for forming so-called via lands at interlayer parts betweenthe dielectric layers 130 c to 130 f.

Moreover, the connection substrate 13 further has a plurality ofinterlayer wirings 24. The interlayer wiring 24 is a wiring caused by adifference between the electrode pitch of the two-dimensional photodiodearray 12 and the pitch of the plurality of through conductors 20. Theinterlayer wiring 24 is provided, out of the interlayer parts in theplurality of dielectric layers 130 a to 130 f, at one or two or moreinterlayer parts located closer to the one substrate surface 13 arelative to the dielectric layers 130 c to 130 f provided with theradiation shielding films 21 a to 23 a. In FIG. 2, the interlayer wiring24 is provided at an interlayer part between the dielectric layer 130 aand the dielectric layer 130 b, and at an interlayer part between thedielectric layer 130 b and the dielectric layer 130 c.

Here, description will be given of a relative positional relationshipbetween the radiation shielding films 21 a to 23 a of the connectionsubstrate 13 and the plurality of unit circuit regions 14 b of theintegrated circuit device 14. For this description, the concept of avirtual plane to project the radiation shielding films and unit circuitregions will be introduced. The virtual plane is defined as a planenormal to a predetermined direction, which is the incident direction ofradiation R shown in FIG. 1. Alternatively, when said incident directionis substantially normal to the substrate surfaces 13 a, 13 b of theconnection substrate 13, the virtual plane may be defined as a planeparallel to the substrate surface 13 a or 13 b.

FIG. 5 is a view showing projection of the pluralities of radiationshielding films 21 a to 23 a of the connection substrate 13 and theplurality of unit circuit regions 14 b of the integrated circuit device14 onto a virtual plane VP. In FIG. 5, reference sign PR1 denotes firstregions obtained by projecting the pluralities of radiation shieldingfilms 21 a to 23 a onto the virtual plane VP. Reference sign PR2 denotessecond regions obtained by projecting the plurality of unit circuitregions 14 b onto the virtual plane VP. Reference sign PR3 denotes thirdregions obtained by projecting the plurality of through conductors 20onto the virtual plane VP.

As shown in FIG. 5, each of the plurality of first regions PR1 obtainedby projecting the pluralities of radiation shielding films 21 a to 23 aonto the virtual plane VP includes each of the plurality of secondregions PR2 obtained by projecting the plurality of unit circuit regions14 b onto the virtual plane VP. In other words, when viewed from theincident direction of radiation R or a direction normal to the substratesurface 13 a, the plurality of unit circuit regions 14 b are completelycovered with the plurality of radiation shielding films 21 a. The sameapplies to the plurality of radiation shielding films 22 a and theplurality of radiation shielding films 23 a.

That is, in the radiation detector module 10A of the present embodiment,each of the pluralities of radiation shielding films 21 a to 23 a formedinside the connection substrate 13 protects each corresponding unitcircuit region 14 b from radiation. Moreover, radiation R that haspassed through the gaps between the pluralities of radiation shieldingfilms 21 a to 23 a can reach the integrated circuit device 14, but nounit circuit regions 14 b exist at that part of arrival, so that thereis little influence from the radiation R.

Moreover, each of the plurality of radiation shielding films 21 a isformed integrally with the corresponding through conductor 20. The sameapplies to the pluralities of radiation shielding films 22 a and 23 a.Thus, the radiation shielding films 21 a to 23 a formed integrally withthe through conductors 20 do not obstruct arrangement of the throughconductors 20, so that it is not necessary to form a complicated wiringsuch as to bypass a radiation shield as in, for example, the devicedescribed in Patent Document 1. Therefore, the current path and wiringlength between the two-dimensional photodiode array 12 and theintegrated circuit device 14 can be reduced, and noise to besuperimposed on electrical signals such as a photoelectric current canbe further reduced.

Thus, by the radiation detector module 10A of the present embodiment,the readout circuits of the integrated circuit device 14 can beprotected from radiation with a simple configuration.

Moreover, in the radiation detector module 10A, because the plurality ofunit circuit regions 14 b of the integrated circuit device 14 areseparated from each other, noise to be generated by electrical crosstalkbetween the plurality of unit circuit regions 14 b can also be reduced.

Moreover, in the radiation detector module 10A, the first region PR1 forthe radiation shielding film 21 a, 21 b, or 21 c formed integrally withone through conductor 20 in one interlayer part and the first region PR1for the radiation shielding film 21 b, 21 c, or 21 a formed integrallywith another through conductor 20 in another interlayer part may notoverlap each other. In the virtual plane VP shown in FIG. 5, theplurality of first regions PR1 do not overlap each other, and projectionregions relating to the radiation shielding films 21 a to 23 a are allfirst regions PR1 and coincident with each other, and thus the radiationshielding films 21 a to 23 a do not overlap each other as long as thesecorrespond to different through conductors 20. Accordingly, theradiation shielding films 21 a to 23 a formed integrally with onethrough conductor 20 and the radiation shielding films 21 a to 23 aformed integrally with another through conductor 20 are not opposed toeach other, so that a parasitic capacitance to be generated between theplurality of through conductors 20 can be reduced. Therefore, noise tobe superimposed on electrical signals such as photoelectric currentsoutput from the plurality of photodiodes of the two-dimensionalphotodiode array 12 can be reduced.

Also, in the present embodiment, as shown in FIG. 5, each of theplurality of third regions PR3 of projection of the plurality of throughconductors 20 onto the virtual plane VP is included in each of theplurality of second regions PR2. In such a configuration, because theradiation shielding films 21 a to 23 a are extended around thecorresponding through conductors 20, each of the radiation shieldingfilms 21 a to 23 a can suitably protect each corresponding unit circuitregion 14 b from radiation.

FIG. 6 is a view showing a configuration of a radiation detector module10B as a modification of the embodiment described above. In FIG. 6,similar to FIG. 2, the two-dimensional photodiode array 12, theconnection substrate 13, and the integrated circuit device 14 are shown.Of these, the two-dimensional photodiode array 12 and the integratedcircuit device 14 have the same configuration as that of the embodimentdescribed above.

In the present modification, the internal configuration of theconnection substrate 13 is different from that of the above-describedembodiment. That is, the radiation shielding film groups 21 and 22 ofthe connection substrate 13 include radiation shielding films 21 b and22 b in place of the radiation shielding films 21 a and 22 a of theabove-described embodiment. The position and size of these radiationshielding films 21 b and 22 b are different from the position and sizeof the radiation shielding films 21 a and 22 a of the above-describedembodiment.

FIG. 7 is a view showing projection of the pluralities of radiationshielding films 21 b and 22 b and the plurality of unit circuit regions14 b of the integrated circuit device 14 onto a virtual plane VP in thepresent modification. In FIG. 7, reference sign PR4 denotes regionsobtained by projecting the radiation shielding films 21 b onto thevirtual plane VP. Reference sign PR5 denotes regions obtained byprojecting the radiation shielding films 22 b onto the virtual plane VP.Reference signs PR2 and PR3 are the same as those in the above-describedembodiment.

As shown in FIG. 7, in the present modification, the region PR4 for theradiation shielding film 21 b formed integrally with one throughconductor 20 in one interlayer part and the region PR5 for the radiationshielding film 22 b formed integrally with another through conductor 20in another interlayer part overlap each other. In such a case, as shownin FIG. 6, the radiation shielding film 21 b formed integrally with onethrough conductor 20 and the radiation shielding film 22 b formedintegrally with another through conductor 20 are opposed to each other.However, even in such a mode, each of the pluralities of radiationshielding films 21 b, 22 b, and 23 a protects each corresponding unitcircuit region 14 b from radiation. Moreover, the radiation shieldingfilms 21 b, 22 b, and 23 a formed integrally with the through conductors20 do not obstruct arrangement of the through conductors 20, so that itis not necessary to form a complicated wiring such as to bypass aradiation shield. Therefore, also in the radiation detector module 10Bof the present modification, the readout circuits of the integratedcircuit device 14 can be protected from radiation with a simpleconfiguration.

The radiation detector module according to the present invention is notlimited to the embodiment described above, and various othermodifications can be made. For example, in the above-describedembodiment, the radiation shielding films 21 a to 23 a are provided atthe three interlayer parts in the four dielectric layers 130 c to 130 f,but radiation shielding films can provide the same effects as those inthe above-described embodiment by being provided at two or moreinterlayer parts in at least three dielectric layers. Moreover, forexample, in the above-described embodiment, an integrator circuitincluding an operational amplifier, a capacitor, and a MOS transistorhas been exemplified as an example of a readout circuit, but even by areadout circuit having a configuration different from that of theexemplification, the same effects as those in the above-describedembodiment can be suitably obtained.

INDUSTRIAL APPLICABILITY

The present invention can be applied as a radiation detector modulecapable of protecting readout circuits of an integrated circuit devicefrom radiation with a simple configuration.

REFERENCE SIGNS LIST

10A, 10B: radiation detector module, 11: scintillator, 12:two-dimensional photodiode array, 12 a: bump electrode, 12 b:photodiode, 13: connection substrate, 13 a, 13 b: substrate surface, 14:integrated circuit device, 14 a: bump electrode, 14 b: unit circuitregion, 14 c: circuit region, 14 d: A/D converter, 14 e: input pad, 14f: input/output pad, 15: flexible printed board, 16: heat sink, 20:through conductor, 21, 22, 23: radiation shielding film group, 21 a, 21b, 22 a, 22 b, 23 a: radiation shielding film, 24: interlayer wiring,130: base material, 130 a˜130 f: dielectric layer, 140: readout circuit,141: operational amplifier, 142: capacitor, 143: reset switch.

The invention claimed is:
 1. A radiation detector module comprising: ascintillator for converting radiation made incident from a predetermineddirection to light; a photoelectric conversion device having a pluralityof photoelectric conversion regions arrayed two-dimensionally, and forreceiving light from the scintillator at the photoelectric conversionregions; a connection substrate formed by stacking a plurality ofdielectric layers, and mounted with the photoelectric conversion deviceon one substrate surface thereof; and an integrated circuit devicemounted on the other substrate surface of the connection substrate, andfor individually reading out electrical signals output from each of theplurality of photoelectric conversion regions of the photoelectricconversion device, the integrated circuit device having a plurality ofunit circuit regions arrayed two-dimensionally and separated from eachother, the plurality of unit circuit regions including a plurality ofreadout circuits corresponding to the plurality of photoelectricconversion regions, respectively, the connection substrate having aplurality of metallic through conductors provided penetrating through atleast three dielectric layers adjacent to each other out of theplurality of dielectric layers, and for serving as a part of paths forthe electric signals, wherein a plurality of metallic radiationshielding films are formed integrally with each of the plurality ofthrough conductors and separated from each other, the radiationshielding films being provided at two or more interlayer parts in the atleast three dielectric layers, and each of a plurality of first regionsof projection of the plurality of radiation shielding films onto avirtual plane normal to the predetermined direction includes each of aplurality of second regions of projection of the plurality of unitcircuit regions onto the virtual plane.
 2. The radiation detector moduleaccording to claim 1, wherein the first region for the radiationshielding film formed integrally with one through conductor in oneinterlayer part and the first region for the radiation shielding filmformed integrally with another through conductor in another interlayerpart do not overlap each other.
 3. The radiation detector moduleaccording to claim 1, wherein each of a plurality of third regions ofprojection of the plurality of through conductors onto the virtual planeis included in each of the plurality of second regions, and eachradiation shielding film is extended around each corresponding throughconductor.
 4. The radiation detector module according to claim 1,wherein the readout circuit includes an operational amplifier, acapacitor, and a MOS transistor.
 5. A radiation detector modulecomprising: a scintillator for converting radiation to light; aphotoelectric conversion device having a plurality of photoelectricconversion regions arrayed two-dimensionally, and for receiving lightfrom the scintillator at the photoelectric conversion regions; aconnection substrate formed by stacking a plurality of dielectriclayers, and mounted with the photoelectric conversion device on onesubstrate surface thereof; and an integrated circuit device mounted onthe other substrate surface of the connection substrate, and forindividually reading out electrical signals output from each of theplurality of photoelectric conversion regions of the photoelectricconversion device, the integrated circuit device having a plurality ofunit circuit regions arrayed two-dimensionally and separated from eachother, the plurality of unit circuit regions including a plurality ofreadout circuits corresponding to the plurality of photoelectricconversion regions, respectively, the connection substrate having aplurality of metallic through conductors provided penetrating through atleast three dielectric layers adjacent to each other out of theplurality of dielectric layers, and for serving as a part of paths forthe electric signals, wherein a plurality of metallic radiationshielding films are formed integrally with each of the plurality ofthrough conductors and separated from each other, the radiationshielding films being provided at two or more interlayer parts in the atleast three dielectric layers, and each of a plurality of first regionsof projection of the plurality of radiation shielding films onto avirtual plane parallel to the one substrate surface includes each of aplurality of second regions of projection of the plurality of unitcircuit regions onto the virtual plane.
 6. The radiation detector moduleaccording to claim 5, wherein the first region for the radiationshielding film formed integrally with one through conductor in oneinterlayer part and the first region for the radiation shielding filmformed integrally with another through conductor in another interlayerpart do not overlap each other.
 7. The radiation detector moduleaccording to claim 5, wherein each of a plurality of third regions ofprojection of the plurality of through conductors onto the virtual planeis included in each of the plurality of second regions, and eachradiation shielding film is extended around each corresponding throughconductor.
 8. The radiation detector module according to claim 5,wherein the readout circuit includes an operational amplifier, acapacitor, and a MOS transistor.